On macOS, gcc is an alias to clang: ``` GCC version Apple LLVM version 9.1.0 (clang-902.0.39.2) Target: x86_64-apple-darwin17.4.0 Thread model: posix InstalledDir: /Applications/Xcode-9.4.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin ``` https://travis-ci.org/teor2345/tor/jobs/421941946#L35 Doc update: https://github.com/travis-ci/docs-travis-ci-com/pull/2002 If we want to use gcc on OS X, we have to set a specific GCC version in the environmental variables: https://docs.travis-ci.com/user/languages/c/#gcc-on-os-x Edit: canonical URL